Process for hydrogenating distillation extraction products from coals



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PROCESS FOR HYDROGENATING DIHSTILLATIN EXTRCTION PRODUCTS FROM COAL Filed Deo. '3, 193s Coal /ASoZz/e Pulp Ex frac Pure Fz'lra/e l)Vif/wai olzfelz Patented Jan. 12, 1943 l u 'rss rg trice I PROCESS FOR HYDROGENATING DISTILLA- TION EXTRACTION PRODUCTS FROM GOALS Application December 3, 1938, Serial N0. 243,876 In Germany December 13, 1937 5 Claims.

In the high pressure hydrogenation, with or without catalysts, of distillation and extraction products from mineral coals, brown coals, peat and so forth, the throughput is reduced owing to the fact that the constituents which are not broken down to distillable oils and benzines on the rst passage through the hydrogenation apparatus, which constituents are drawn oi as sludge in the hot separator, have to be led through the hydrogenation apparatus again and again until these portions also are broken down to distillable oils. Since in the case of these constituents we are dealing with the portions' of the starting products introduced which are the most diicult to hydrogenate, the total throughput of the hydrogenation apparatus, quite apart from the repeated passage of these portions through the reaction space, is additionally aggravated owing to their more difcult hydrogenation capabilities.

According to the present invention these diniculties are overcome and maximum throughputs obtained in the hydrogenation of coal extracts, pitch and so forth, by continuously withdrawing a part of the sludge arising in the hot separator and adding it to the crude coal extract solutions before the ltration. In this way the solid substances accumulating in the sludge, such as for example the so-called free carbon from pitch, ash accumulations and the like, are separated 01T by the filtration of the crude coal extract solutions and getinto the ash-containing residual coal of the extraction, with which they are then burned after expulsion of the extraction oils, for example in boiler iirings. The oily and reactive portions of the sludge, however, pass into the pure filtrate and, after expulsion of the extraction agent, are together with the coal extracts supplied again to the hydrogenation.

In certain cases, in the common hydrogenation of coal extracts and tar pitches it may be advisable to admix the pitch with the crude coal extract solutions before the filtration so that the ash constituents of the pitch and its portions of so-called free carbon are separated oii right from the first and led away together with the ashcontaining residual coal of the coal extraction and for example used in firing. In the pure ltrate there are then the ash-free and solid-free, and consequently readily hydrogenated, portions of the pitch together with the coal extract. After expulsion of the solvent, the mixture of pitch and coal extract is then supplied to the high pressure hydrogenation. In this case also diicultly reactive fractions which have become inlhvdrogenation.

The employment of raised pressures of above 300 atm. gauge pressure, more particularly pressures of 40G-700 atm. gauge pressure and more, ensures a complete decomposition or degradation of the crude substances introduced. According to the manner of working provided by the invention throughputs are forthwith obtained amounting to 0.3 kg. up to above 1 kg. and more per litre of reaction space per hour.

The accompanying drawing represents a now sheet showing the steps comprised in the process of the present invention.

The following example illustrates the process provided by the present invention.

A mineral coal from the Ruhr is stirred up with a middle oil which is obtained in the subsequent joint hydrogenation of pitch and mineral coal extract, and is led through a high pressure apparatus at a high temperature. The resulting crude extract solution is released from pressure and coo-led down to a lower temperature. To this crude degrade is added a part of the sludge arising in the hot separator of the hydrogenation chamber. Preferably the pitch is also admixed with these crude extract solutions. The mixture of crude degrade, pitch and sludge is then supplied to a pressure filter in which, at a high pressurel and temperature, the ash constituents of the pitch and its portions of so-called free carbon are separated oli together with the ash-containing residual coal of the coal extraction. In the pure iiltrate there arev then, together with the coal extract, the portions of the pitch which are free from ash and solid material and consequently readily hydrogenizable. After Vexpulsion of the solvent, the mixture of pitch and coal extract is then mixed with a relatively high boiling oil and supplied to pressure hydrogenation. In this way great outputs of about l kg. per litre of reaction space per hour are obtained, and the concentration of solids, inorganic fractions and so forth during the high pressure hydrogenation maintained at the desired low amount.

What we claim is:

1. In the process which comprises the steps of extracting coal with a solvent, ltering the extract solution, and hydrogenating the extract, the additional steps of drawing off the substantially unhydrogenated sludge arising in the hydrogenation step and adding it to the crude coal extract solution obtained in the extraction step prior to the ltration thereof.

2. In the process claimed in claim l the step of hydrogenating the extract jointly with products from coal distillation operations.

3. In the process claimed in claim 1 the step of also adding products from coal distillation 'operations to the crude coal extract solution prior to the ltration of the latter.

4. In the process claimed in claim 1 the step 

